Cleaning your MAF sensor.
If your VW is starting to idle rough, hard to start in the cold or mornings, and seems to be loosing power in the rpm range, you could try cleaning your MAF. MAF is the Mass Air Flow sensor installed inline with the air intake tube between the air filter and the throttle body. A VW MAF has an extremely thin wire that can tell how much air is flowing through the engine.
Since the VW MAF is inline with the air intake, it is possible that it is dirty. This is especially true with oil soaked air filters such as K&N. Even though the VW MAF is supposed to become super hot during shut off to clean itself, the MAF Cleaning seems to help on older cars.
Step 1.
Remove the MAF. This varies on each car. Leave the MAF in the housing. It's way to sensitive to risk taking it out, and on the OBDI cars, way to expensive. You can buy new OBDI VR6 MAF for about $300!!
Usually it is as simple as removing a large hose clamp on the intake tube, unhooking the air filter housing top section, and unscrewing the MAF housing from the air filter box. Probably no more than 3 screws on any model.
Step 2.
The Cleaning. You should be spraying the very thin and delicate wire inside the MAF with NOTHING other than a quick dry electronics contact cleaner. No widex, no rubbing alcohol, no brake cleaner, no Q-tips.
Step 3.
Let it dry completely and reinstall.
Step 4.
Drive!
If all went well, the car may run noticeably better. If not check other items such as the TPS, wiring harness and connections, etc. Have a professional scan your ECU for error codes to find out the real problem. Cleaning the MAF is a DIY job to attempt to safe money, but not guaranteed to fix anything.